<script setup>
  import { ref, watch, reactive, computed } from 'vue'

  //本地存储的键名
  const SCORE_LIST_KEY='score-list-key'

  //成绩列表
  const scoreList=ref(
    JSON.parse(localStorage.getItem(SCORE_LIST_KEY)) || [
      { id:19,subject: '语文', score: 94},
      { id:27,subject: '数学', score: 58},
      { id:12,subject: '英语', score: 92}
    ]
  )

  //成绩表单
  const scoreForm=reactive({
    subject: '',
    score: ''
  })

  //添加
  const onAdd=()=>{
    //非空校验
    if(!scoreForm.subject || !scoreForm.score){
      return alert('科目名称或成绩不能为空')
    }
    //给数组新增对象
    scoreList.value.push({
      ...scoreForm, //展开scoreForm
      id:Date.now()
    })
    //清空表单
    scoreForm.subject=scoreForm.score=''
  }

  //删除
  const onDel=(i)=>{
    if(window.confirm('确认删除吗？')){
      scoreList.value.splice(i,1)
    }
  }

  //计算得到总分数
  const totalScore=computed(()=>{
    return scoreList.value.reduce((prev,item)=> prev+item.score,0)
  })

  //计算平均分
  const avgScore=computed(()=>{
    return scoreList.value.length>0?
    totalScore.value/scoreList.value.length:0
  })

  watch(scoreList,(newVal)=>{
    //监视scoreList的变化，当scoreList变了，将最新的值进行序列化后，存储到本地
    localStorage.setItem(SCORE_LIST_KEY,JSON.stringify(newVal))
  },
  {
    //开启深度监视
    deep:true
  })
</script>

<template>
  <div class="score-case">
    <div class="table">
      <table>
        <thead>
          <tr>
            <th>编号</th>
            <th>科目</th>
            <th>成绩</th>
            <th>操作</th>
          </tr>
        </thead>
        <tbody>
          <!-- 列表渲染 -->
          <tr v-for="(item, index) in scoreList" :key="item.id">
            <td>{{ index + 1 }}</td>
            <td>{{ item.subject }}</td>
            <td :class="{ red: item.score < 60 }">{{ item.score }}</td>
            <td>
              <a href="#" @click="onDel(index)">删除</a>
            </td>
          </tr>
        </tbody>
        <tbody v-if="scoreList.length === 0">
          <tr>
            <td colspan="5">
              <span class="none">暂无数据</span>
            </td>
          </tr>
        </tbody>
        <tfoot>
          <tr>
            <td colspan="5">
              <span>总分:{{ totalScore }}</span>
              <span style="margin-left:50px">平均分:{{ avgScore }}</span>
            </td>
          </tr>
        </tfoot>
      </table>
    </div>
    <form class="form">
      <div class="form-item">
        <div class="label">科目:</div>
        <div class="input">
          <input type="text" v-model.trim="scoreForm.subject" placeholder="请输入科目">
        </div>
      </div>
      <div class="form-item">
        <div class="label">分数:</div>
        <div class="input">
          <input type="number" v-model.number="scoreForm.score" placeholder="请输入成绩">
        </div>
      </div>
      <div class="form-item">
        <div class="label"></div>
        <div class="input">
          <button class="submit" @click.prevent="onAdd">添加</button>
        </div>
      </div>
    </form>
  </div>
</template>


<style>
.score-case {
  width: 1000px;
  margin: 50px auto;
  display: flex;
}

.score-case .table {
  flex: 4;
}

.score-case .table table {
  width: 100%;
  border-spacing: 0;
  border-top: 1px solid #ccc;
  border-left: 1px solid #ccc;
}

.score-case .table table th {
  background: #f5f5f5;
}

.score-case .table table tr:hover td {
  background: #f5f5f5;
}

.score-case .table table td,
.score-case .table table th {
  border-bottom: 1px solid #ccc;
  border-right: 1px solid #ccc;
  text-align: center;
  padding: 10px;
}

.score-case .table table td.red,
.score-case .table table th.red {
  color: red;
}

.score-case .table .none {
  height: 100px;
  line-height: 100px;
  color: #999;
}

.score-case .form {
  flex: 1;
  padding: 20px;
}

.score-case .form .form-item {
  display: flex;
  margin-bottom: 20px;
  align-items: center;
}

.score-case .form .form-item .label {
  width: 60px;
  text-align: right;
  font-size: 14px;
}

.score-case .form .form-item .input {
  flex: 1;
}

.score-case .form .form-item input,
.score-case .form .form-item select {
  appearance: none;
  outline: none;
  border: 1px solid #ccc;
  width: 200px;
  height: 40px;
  box-sizing: border-box;
  padding: 10px;
  color: #666;
}
.score-case .form .form-item input::placeholder {
color: #666;
}
.score-case .form .form-item .cancel,
.score-case .form .form-item .submit {
appearance: none;
outline: none;
border: 1px solid #ccc;
border-radius: 4px;
padding: 4px 10px;
margin-right: 10px;
font-size: 12px;
background: #ccc;
}
.score-case .form .form-item .submit {
border-color: #069;
background: #069;
color: #fff;
}
</style>